# File activerecord/lib/active_record/core.rb, line 90defself.disable_implicit_join_references=(value)
ActiveSupport::Deprecation.warn(" Implicit join references were removed with Rails 4.1.
Make sure to remove this configuration because it does nothing.
".squish)
end

New objects can be instantiated as either empty (pass no construction
parameter) or pre-set with attributes but not yet saved (pass a hash with
key names matching the associated table column names). In both instances,
valid attribute keys are determined by the column names of the associated
table – hence you can't have attributes that aren't part of the
table columns.

Example:

# File activerecord/lib/active_record/core.rb, line 272definitialize(attributes = nil, options = {})
@attributes = self.class._default_attributes.dupself.class.define_attribute_methodsinit_internalsinitialize_internals_callback# +options+ argument is only needed to make protected_attributes gem easier to hook.# Remove it when we drop support to this gem.init_attributes(attributes, options) ifattributesyieldselfifblock_given?run_callbacks:initializeend

Returns true if comparison_object is the same exact object, or
comparison_object is of the same type and self
has an ID and it is equal to comparison_object.id.

Note that new records are different from any other record by definition,
unless the other record is the receiver itself. Besides, if you fetch
existing records with select and leave the ID out, you're
on your own, this predicate will return false.

Note also that destroying a record preserves its ID in the model instance,
so deleted models are still comparable.

Identical to Ruby's clone method. This is a “shallow” copy. Be warned
that your attributes are not copied. That means that modifying attributes
of the clone will modify the original, since they will both point to the
same attributes hash. If you need a copy of your attributes hash, please
use the dup method.

Duped objects have no id assigned and are treated as new records. Note that
this is a “shallow” copy as it copies the object's attributes only, not
its associations. The extent of a “deep” copy is application specific and
is therefore left to the application to implement according to its need.
The dup method does not preserve the timestamps (created|updated)_(at|on).